table of contents - egram.co.hennepin.mn.us135+… · deep foundations - driven piles ... table of...
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Table of Contents
Description Page A. Introduction ...................................................................................................................................... 1
A.1. Project Description .............................................................................................................. 1
A.2. Purpose ................................................................................................................................ 1
A.3. Background Information and Reference Documents .......................................................... 1
A.4. Site Conditions..................................................................................................................... 1
A.5. Scope of Services ................................................................................................................. 2
B. Results .............................................................................................................................................. 2
B.1. Boring Locations and Elevations .......................................................................................... 2
B.2. Exploration Logs .................................................................................................................. 3
B.2.a. Log of Boring Sheets ............................................................................................... 3
B.2.b. Geologic Origins ..................................................................................................... 3
B.3. Geologic Profile ................................................................................................................... 3
B.3.a. Pavement Section ................................................................................................... 3
B.3.b. Fill ........................................................................................................................... 4
B.3.c. Swamp Deposits ..................................................................................................... 4
B.3.d. Alluvial Deposits ..................................................................................................... 4
B.3.e. Glacial Deposits ...................................................................................................... 4
B.3.f. Groundwater .......................................................................................................... 5
B.4. Laboratory Test Results ....................................................................................................... 5
C. Basis for Recommendations ............................................................................................................. 5
C.1. Design Details ...................................................................................................................... 5
C.1.a. Bridge Foundation Loads and Pile Types ................................................................ 5
C.1.b. Bridge Approach Embankments ............................................................................. 6
C.1.c. Wing/Retaining Walls ............................................................................................. 6
C.1.d. Anticipated Grade Changes .................................................................................... 6
C.1.e. Precautions Regarding Changed Information ........................................................ 6
C.2. Design Considerations ......................................................................................................... 6
C.3. Construction Considerations ............................................................................................... 7
D. Recommendations ........................................................................................................................... 7
D.1. Deep Foundations - Driven Piles ......................................................................................... 7
D.1.a. Calculation Method ................................................................................................ 7
D.1.b. Assumptions ........................................................................................................... 8
D.1.c. Pile Capacities ......................................................................................................... 8
D.1.d. Pile Settlement ..................................................................................................... 10
D.1.e. Pile Specification and Driving ............................................................................... 10
D.1.f. Lateral Earth Pressure Calculations for P-Y Curves and Lateral Earth Forces ...... 10
D.1.g. Pile Spacing and Group Effect .............................................................................. 11
D.1.h. Pile Driving System ............................................................................................... 11
D.2. Bridge Approach Embankments ........................................................................................ 12
Table of Contents (continued)
Description Page
D.2.a. Subgrade Preparation .......................................................................................... 12
D.2.b. Backfill and Compaction ....................................................................................... 12
D.2.c. Design Soil Parameters ......................................................................................... 12
D.2.d. Embankment Settlement ..................................................................................... 12
D.3. Retaining Walls .................................................................................................................. 13
D.3.a. Foundations .......................................................................................................... 13
D.3.b. Drainage Control .................................................................................................. 13
D.3.c. Selection, Placement and Compaction of Backfill ................................................ 13
D.3.d. Configuring and Resisting Lateral Loads............................................................... 14
D.4. Construction Quality Control ............................................................................................ 14
D.4.a. Observations ........................................................................................................ 14
D.4.b. Materials Testing .................................................................................................. 14
D.4.c. Pile Quality Control .............................................................................................. 14
D.4.d. Cold Weather Precautions ................................................................................... 15
E. Procedures...................................................................................................................................... 15
E.1. Penetration Test Borings ................................................................................................... 15
E.2. Material Classification and Testing ................................................................................... 15
E.2.a. Visual and Manual Classification .......................................................................... 15
E.2.b. Laboratory Testing ............................................................................................... 16
E.3. Groundwater Measurements ............................................................................................ 16
F. Qualifications .................................................................................................................................. 16
F.1. Variations in Subsurface Conditions .................................................................................. 16
F.1.a. Material Strata ..................................................................................................... 16
F.1.b. Groundwater Levels ............................................................................................. 16
F.2. Continuity of Professional Responsibility .......................................................................... 17
F.2.a. Plan Review .......................................................................................................... 17
F.2.b. Construction Observations and Testing ............................................................... 17
F.3. Use of Report..................................................................................................................... 17
F.4. Standard of Care ................................................................................................................ 17
Appendix Boring Location Sketch Log of Boring Sheets: ST-1 and ST-2 Laboratory Test Results Descriptive Terminology
A. Introduction
A.1. Project Description
This Geotechnical Evaluation Report addresses the proposed reconstruction of Bridge No. 90621 along
CSAH 135 over the Maxwell Channel in Orono, Minnesota. The bridge is anticipated to have tall parapet
abutments with long wing walls that may become retaining walls.
Our services on this project also included performing a Limited Phase I Environmental Site Assessment
and an Asbestos and Regulated Waste Assessment. These assessments will be provided under separate
cover.
A.2. Purpose
The purpose of the geotechnical evaluation is to characterize subsurface geologic conditions at selected
exploration locations and evaluate their impact on the design and construction of the bridge
replacement.
A.3. Background Information and Reference Documents
To facilitate our evaluation, we were provided with or reviewed the following information or documents:
Project Location Map, dated June 7, 2011.
Email and phone correspondences between Braun Intertec and Hennepin County.
We reviewed aerial photographs of the project site using Google Earth®.
A.4. Site Conditions
The site currently resides as an existing two lane overpass bridge that was constructed in 1930. Bridge
90621 is a one span bridge with an approximate structure length of 33 feet. The main span is supported
by steel beams with a treated timber deck material and a bituminous wear surface.
Hennepin County Transportation Department Project B14-04099 September 3, 2014 Page 2
A.5. Scope of Services
Our scope of services for this project was originally submitted as a Proposal for a Geotechnical
Evaluation. We received authorization to proceed from Mr. James Archer on June 11, 2014. Tasks
completed in accordance with our authorized scope of services are described below.
Staking and clearing exploration locations of underground utilities.
Performing two penetration test borings to depths to meet the MnDOT 2500 aggregate blow
count criteria.
Providing flaggers to safely facilitate completion of the penetration test borings along two
lane CSAH 135.
Performing laboratory testing on selected penetration test samples collected in the field to
meet MnDOT requirements.
Performing one Hveem Stabilometer R-value test and associated standard proctor test.
Preparing this report containing a CAD sketch, exploration logs, a summary of the geologic
materials encountered, results of laboratory tests, and recommendations for structure
subgrade preparation and foundation design of the replacement bridge.
Our scope of services was performed under the terms of our First Amendment to our Master Service
contract with Hennepin County under Contract number A101903.
B. Results
B.1. Boring Locations and Elevations
We performed two standard penetration test soil borings for our evaluation, denoted as ST-1 and ST-2.
Boring ST-1 was located on the north side of the channel bridge and Boring ST-2 was located on the south
side. The approximate locations are shown on the Soil Boring Location Sketch included in the Appendix.
Hennepin County Transportation Department Project B14-04099 September 3, 2014 Page 3
The borings locations were selected by Hennepin County and staked by Braun Intertec personnel.
Exploration surface elevations at the exploration locations were determined using GPS (Global
Positioning System) technology that utilizes the Minnesota Department of Transportation's permanent
GPS Virtual Reference Network (VRN).
B.2. Exploration Logs
B.2.a. Log of Boring Sheets
Log of Boring sheets for our penetration test borings are included in the Appendix. The logs identify and
describe the geologic materials that were penetrated, and present the results of penetration resistance
tests performed within them, laboratory tests performed on penetration test samples retrieved from
them, and groundwater measurements.
Strata boundaries were inferred from changes in the penetration test samples and the auger cuttings.
Because sampling was not performed continuously, the strata boundary depths are only approximate.
The boundary depths likely vary away from the boring locations, and the boundaries themselves may
also occur as gradual rather than abrupt transitions.
B.2.b. Geologic Origins
Geologic origins assigned to the materials shown on the logs and referenced within this report were
based on: (1) a review of the background information and reference documents cited above, (2) visual
classification of the various geologic material samples retrieved during the course of our subsurface
exploration, (3) penetration resistance testing performed for the project, (4) laboratory test results, and
(5) available common knowledge of the geologic processes and environments that have impacted the
site and surrounding area in the past.
B.3. Geologic Profile
The types of soils encountered in the borings are described below. The soils are generally described in
the order they were encountered; i.e., beginning at the ground surface. Please refer to the soil boring
logs in the Appendix for a more in-depth summary of the observed soils.
B.3.a. Pavement Section
Borings ST-1 and ST-2 both encountered a bituminous pavement section. Below the pavement section, a
layer of aggregate base was encountered. Based on the condition of the aggregate base material
encountered in the field it does not appear, in its current condition, to consist of a material meeting
Minnesota Department of Transportation (MnDOT) Class 5 or 6 requirements.
Hennepin County Transportation Department Project B14-04099 September 3, 2014 Page 4
Table 1. Approximate Pavement Section Thickness
Boring
Location
Bituminous Thickness (inches)
Aggregate Base Thickness (inches)
ST-1 North side of Bridge 90621 12 12
ST-2 South side of Bridge 90621 18 6
B.3.b. Fill
Below the pavement section, fill soils were encountered in both borings. The fill soils generally consisted
of poorly graded sand with silt, silty sand and clayey sand and were encountered to approximate depths
of 15 and 19 feet (approximate elevation 923 1/2 and 919 1/2) below existing grade in Borings ST-1 and
ST-2, respectively. The recorded penetration resistances in the fill soils ranged from 1 to 15 blows per
foot (BPF), indicating variable levels of compaction within the fill.
B.3.c. Swamp Deposits
Below the fill, swamp deposits were encountered in both borings that generally consisted of partially
decomposed peat and slightly organic lean clay with a trace of shells. The swamp deposits were
encountered to approximate depths of 25 and 24 feet (approximately elevations 913 1/2 and 914 1/2) in
Borings ST-1 and ST-2, respectively.
B.3.d. Alluvial Deposits
Underlying the swamp deposits in Boring ST-1, a layer of alluvium was encountered to a depth of 34 feet
(approximate elevation 904 1/2) below existing grade. The alluvium generally consisted of fat clay and silt
with sand. The recorded penetration resistance in the fat clay was weight of hammer (WH), indicating a
very soft consistency and the recorded penetration resistances in the sandy silt soils ranged from 4 to 9
BPF, indicating very loose to loose relative densities.
B.3.e. Glacial Deposits
Glacial soils were encountered below the alluvium in Boring ST-1 and below the swamp deposits in
Boring ST-2. The glacial soils generally consisted of poorly graded sand, well-graded sand with silt, poorly
graded sand with silt, silty sand, clayey sand, and sandy lean clay. The glacial soils contained variable
amounts of gravel and have the potential to contain cobbles and boulders.
The recorded penetration resistances in the non-cohesive glacial soils (poorly graded sand, well-graded
sand with silt, poorly graded sand with silt and silty sand) ranged from 8 BPF to 50 blows per 6 inches of
penetration, indicating loose to very dense relative densities. The recorded penetration resistances in the
cohesive glacial soils (clayey sand and sandy lean clay) ranged from 9 to 27 BPF, indicating soft to very
stiff consistencies.
Hennepin County Transportation Department Project B14-04099 September 3, 2014 Page 5
B.3.f. Groundwater
Groundwater was measured or estimated to be between approximately 9 to 12 feet below existing grade
as our borings were advanced. These depths correspond to elevations 926 1/2 to 929 1/2 feet Mean Sea
Level (MSL) based on our reported datum. The ground water elevation encountered in the borings is
likely near the surface elevation of the lake, which is near elevation 931 feet MSL when recorded on
July 17, 2014.
Seasonal and annual fluctuations of groundwater should also be anticipated.
B.4. Laboratory Test Results
We performed moisture content, density, organic content and unconfined compressive strength tests on
the thin walled sample collected from Boring ST-1; moisture contents, sieve analyses, organic contents
and an atterberg limit test on selected jar samples from the borings and a standard proctor and R-value
test on the bag sample recovered from Boring ST-1 in accordance with ASTM or AASHTO procedures.
The moisture content test results indicated the in-place soils are generally near to above their estimated
optimum moisture contents. The organic content tests performed on swamp deposits indicated those
layers consisted of peat or slightly organic lean clay. The sieve analyses performed on granular soil
samples collected generally consisted of silty sand or well-graded sand with silt. Atterberg limits
determined the soil sample collected in Boring ST-1 at a depth near 25 feet consisted of fat clay. The R-
value test on the recovered subgrade material in Boring ST-1 indicated an R-value of 12.
The test results are shown on the Log of Boring Sheets included in the appendix, across from the
associated soil sample. The sieve analyses, unconfined compressive strength, standard Proctor and R-
value test results are shown on separate test result sheets included in the Appendix of this report.
C. Basis for Recommendations
C.1. Design Details
C.1.a. Bridge Foundation Loads and Pile Types
Structural details, including anticipated foundation loads, are not available at this time. Based on the soils
encountered in the borings, we have assumed deep foundations to support the new bridge will
experience a factored design load of 100 tons (200 kips) for each 12-inch closed-ended pipe (CEP) pile
and 135 tons (270 kips) for each 16-inch CEP pile.
Hennepin County Transportation Department Project B14-04099 September 3, 2014 Page 6
C.1.b. Bridge Approach Embankments
We have assumed bridge approach embankments are designed for side slopes approximately equal to
those of the existing bridge.
C.1.c. Wing/Retaining Walls
Long wing walls that may become retaining walls are anticipated to retain soils placed along the
approach embankments. Specific details for support of the wing/retaining walls are not known at this
time, but based on the soils borings, we anticipate these structures being supported by driven pile,
similar to the types assumed for support of the new bridge abutments.
C.1.d. Anticipated Grade Changes
We understand existing ground surface elevations are generally consistent (within a couple inches) to the
proposed roadway alignment. Therefore, any fills associated with construction of the new bridge
approaches are considered negligible.
C.1.e. Precautions Regarding Changed Information
We have attempted to describe our understanding of the proposed construction to the extent it was
reported to us by others. Depending on the extent of available information, assumptions may have been
made based on our experience with similar projects. If we have not correctly recorded or interpreted the
project details, we should be notified. New or changed information could require additional evaluation,
analyses and/or recommendations.
C.2. Design Considerations
The geotechnical issues influencing design of a bridge supported on shallow foundations may be
complicated due to the potential for scour of the supporting soils and the presence of swamp deposits
extending between 24 and 25 feet below existing grade. Therefore, we recommend supporting the
proposed bridge on deep foundations.
The presence of medium dense sands and stiff to rather stiff glacial clays at depth makes driven steel CEP
piles the preferred pile type as it appears the depth to reach a hard bearing layer is below the depths
explored by the borings and the majority of the geotechnical resistance will be developed through side
friction resistance.
Hennepin County Transportation Department Project B14-04099 September 3, 2014 Page 7
C.3. Construction Considerations
From a construction perspective, the project team should also be aware that:
The existing fill soils encountered in the borings do not meet MnDOT Specification 3149.2B2
for Select Granular Borrow. Therefore, it is anticipated material for use as abutment backfill
will need to be imported. Much of the existing on-site fill soils, encountered above the
swamp deposits, generally consist of silty sand that can be difficult to reuse as fill due to its
sensitivity to moisture. Moisture conditioning may be necessary to reuse on-site materials as
fill in other areas on the site.
Excavations will penetrate the groundwater surface at a depth of approximately 9 feet, near
the anticipated channel elevation near 831 feet MSL. Depending on the depth of the
proposed abutment foundations, temporary dewatering and placement of crushed rock
likely will be needed to help control groundwater seepage with sumps and provide a stable
working platform during pile installation and placement of the pile caps.
D. Recommendations
In accordance with our findings and correspondences with you, our recommendations for support of the
replacement bridge and approach embankments are provided below.
D.1. Deep Foundations - Driven Piles
At your request and as mentioned in Section C.1.a, we evaluated design requirements for 12-inch and 16-
inch CEP pile sections.
D.1.a. Calculation Method
We used the computer program UniPile, version 5.0.0.33, to estimate the static nominal geotechnical
resistance (Rn) of the 12- and 16-inch outside-diameter, CEP piles for support of the replacement bridge.
UniPile software was developed by UniSoft Geotechnical Solutions Ltd. and can calculate pile resistance
using a variety of methods.
For our analysis, we utilized the Beta-method, an effective stress method, to estimate the static
geotechnical resistance for these pile. This method determines shaft resistance using Bjerrum-Burland
beta coefficients (β), which are based on soil type and effective friction angle. We estimated the β values
Hennepin County Transportation Department Project B14-04099 September 3, 2014 Page 8
for each layer using Figure 9.20 from the Federal Highway Administration (FHWA) Publication No. NHI-
05-042, Design and Construction of Driven Pile Foundations, April 2006. The Beta-method determines
end bearing resistance using toe bearing capacity factors (Nt), which are also based on soil type and
effective friction angle. We estimated the Nt values from Table 9-6 of the April 2006 FHWA publication
identified previously.
There are numerous methods of predicting the static capacities of piles based on the results of borings,
and the results of the various methods often differ by a factor of two or more. Evaluating the nominal
resistance of a pile during or after installation also depends on the method selected. The measured
capacity depends on the method used (dynamic formula, wave equation, Pile Dynamic Analyzer (PDA) or
static load test) and the criteria used with each method.
D.1.b. Assumptions
We based the effective unit weights input into UniPile on estimations of the measured moisture contents
and past experience on other projects. We used the Naval Facilities Engineering Command, Soil
Mechanics Design Manual (pg. 7.1-149, Figure 7) to estimate friction angles of coarse-grained soils. We
estimated the un-drained shear strengths of fine-grained soils based on the SPT values obtained.
We assumed the bottom of pile cap (BOPC) elevations for the north and south abutments will be about
929 feet MSL. We assumed the pile cut-off elevations would be approximately 1 foot above the BOPC
elevations.
D.1.c. Pile Capacities
Factored geotechnical pile capacities are determined by multiplying the pile driving resistance factor
(dynamic) by the nominal pile resistance (Rn). The American Association of State Highway and
Transportation Officials (AASHTO) and the MnDOT recommend relating dynamic to the degree of
construction control. For situations where subsurface exploration and static calculations have been
completed, MnDOT recommends the following dynamic factors.
Table 2. Recommended Pile Driving Resistance Factors
Specified Construction Control dynamic
MnDOT Pile Formula 2012 (MPF12) for Pipe Pile Sections
0.50
Dynamic testing with signal matching (PDA) on at least 2 piles per site condition but not less than 2% of production piles
a 0.65
a Based on Table 10.5.5.2.3-1 of the current AASHTO’s LRFD Bridge Design Specification.
Hennepin County Transportation Department Project B14-04099 September 3, 2014 Page 9
We evaluated the necessary pile lengths to achieve the required geotechnical resistance for the MnDOT
LRFD dynamic pile capacity formula and the wave equation with PDA methods of field control. For the
Mn/DOT LRFD dynamic pile capacity formula method, we used a dynamic of 0.50 to estimate the desired Rn
capacities (Rn = Qn / dynamic). We used a dynamic of 0.65 in our evaluation for the PDA method. If a
different construction control method is performed, the pile lengths or capacities may need to be
revised.
Based on the anticipated factored design load of 100 tons (200 kips) for the 12-inch CEP pile and 135 tons
(270 kips) for the 16-inch CEP pile and the pile driving resistance factors discussed above, we estimated
the pile lengths for nominal resistances for each pile type if the MnDOT MPF 12 Formula and PDA
construction control method is used. The estimated lengths provided in Tables 3, 4, 5 and 6 below are
from the assumed BOPC elevations provided in section D.1.b of this report.
Table 3. Summary of Anticipated Pile Lengths – 12”x1/4” CEP, Qn=100 tons, PDA
Substructure Boring
Cutoff Elevation
(feet) Rn
(tons)
Approximate Tip Elevation
(feet)
Approximate Pile Length (feet)
North Abutment
ST-1 930 154 845 85
South Abutment
ST-2 930 154 850 80
Table 4. Summary of Anticipated Pile Lengths – 12”x1/4” CEP, Qn=100 tons, MPF 12
Substructure Boring
Cutoff Elevation
(feet) Rn
(tons)
Approximate Tip Elevation
(feet)
Approximate Pile Length (feet)
North Abutment
ST-1 930 200 835 95
South Abutment
ST-2 930 200 840 90
Table 5. Summary of Anticipated Pile Lengths – 16”x1/4” CEP, Qn=135 tons, PDA
Substructure Boring
Cutoff Elevation
(feet) Rn
(tons)
Approximate Tip Elevation
(feet)
Approximate Pile Length (feet)
North Abutment
ST-1 930 208 850 80
South Abutment
ST-2 930 208 855 75
Hennepin County Transportation Department Project B14-04099 September 3, 2014 Page 10
Table 6. Summary of Anticipated Pile Lengths – 16”x1/4” CEP, Qn=135 tons, MPF 12
Substructure Boring
Cutoff Elevation
(feet) Rn
(tons)
Approximate Tip Elevation
(feet)
Approximate Pile Length (feet)
North Abutment
ST-1 930 270 840 90
South Abutment
ST-2 930 270 845 85
As stated in section C.3, the majority of the geotechnical resistance will be developed through skin
friction, therefore, we recommend supporting the new bridge structure on driven pipe piles. The depths
estimated in Tables 3 through 6 are estimated based on inferred strata changes shown in the borings,
actual site conditions may vary.
D.1.d. Pile Settlement
We anticipate total and differential deformation of the pile heads will be less than 1 inch under the
assumed loads. Driven with the aforementioned design or construction control methods, driven pile is
not designed to settle. The majority of deformation at the pile head is due to elastic shortening of the
pile under the design loads.
D.1.e. Pile Specification and Driving
We anticipate the pipe piles will conform to MnDOT Specification 2452 and 3371. The minimum required
wall thickness is 1/4 inch.
If a pile's resistance to driving is not obtained at the anticipated length, we recommend driving be halted,
and that the capacity be evaluated on restrike after a wait period of at least 3 days. If the pile toe is
driven past the estimated toe elevations shown in Tables 3, 4, 5 and 6, it is probable the piles have been
overdriven and, after soil setup occurs, the pile capacities will be adequate. The MPF12 pile installation
construction control criterion is much more likely to cause overdriving of pile deeper than necessary than
the PDA method.
D.1.f. Lateral Earth Pressure Calculations for P-Y Curves and Lateral Earth Forces
The following table provides earth pressure soil parameters for lateral pile analysis and p-y curve
generation using the current version of the computer program LPILE. Based on the soils encountered in
the borings, we recommend using the default lateral modulus of subgrade reaction values included in
LPILE.
Hennepin County Transportation Department Project B14-04099 September 3, 2014 Page 11
Table 7. Soil Parameters for p-y Curve Generation
Layer Top Depth Below
Existing Grade (feet)
Layer Bottom Depth Below
Existing Grade (feet)
Effective Unit Weight
(pounds per cubic foot)
Internal Angle of Friction
(degrees)
Undrained Shear Strength
(pounds per square foot) Material Type
0 9 120 27 NA Sand (Reese)
9 15 58 27 NA Sand (Reese)
15 27 15 NA 150 Soft Clay (Matlock)
27 34 58 30 NA Sand (Reese)
34 42 58 31 NA Sand (Reese)
42 74 63 NA 1200 Stiff Clay without
Free Water (Reese)
74 117 63 NA 1800 Stiff Clay without
Free Water (Reese)
117 120 56 40 NA Sand (Reese)
D.1.g. Pile Spacing and Group Effect
In our opinion, the nominal vertical resistances of piles spaced at least 3 pile diameters apart need not be
reduced due to group effects. If a closer spacing is ultimately selected, we recommend having a
geotechnical engineer evaluate the magnitude of the group effect, and the extent to which the nominal
resistances should be reduced.
If pile layout and spacing dictates, the calculated lateral pile capacities are recommended to be reduced
by p-multipliers identified in Table 10.7.2.4-1 of the recent AASHTO’s LRFD Bridge Design Specification.
For a more refined analysis, GROUP or similar pile analysis software could be used to develop
appropriate shading factors based on the interaction between the actual pile spacing with the soil
conditions encountered at each substructure unit.
D.1.h. Pile Driving System
Using an under or oversized pile-driving hammer can be detrimental to the successful installation of
piling. Prior to system acceptance, we therefore recommend performing a wave equation analysis
modeling prospective contractors’ pile installation systems. The wave equation analysis is used to
estimate probable driving stresses and pile penetration resistance based on the type of hammer
proposed, the specified pile type/size and the site-specific material conditions which, when combined,
help evaluate system suitability. Our firm can discuss the requirements and limitations of wave equation
analyses and, if needed, perform them.
Hennepin County Transportation Department Project B14-04099 September 3, 2014 Page 12
D.2. Bridge Approach Embankments
D.2.a. Subgrade Preparation
We recommend the pavements (within the existing roadway) and topsoil, organic soil or loose fill
(outside of the existing pavements) be removed from the proposed fill and pavement areas after site
stripping is complete. We recommend the subgrade be surface compacted with a self-propelled vibratory
sheepsfoot compactor. The purpose of the surface compaction is to densify any loose fill and to provide a
more uniform subgrade for fill support.
D.2.b. Backfill and Compaction
Fill should consist of debris-free, non-organic mineral soil placed in a controlled manner. We recommend
the abutment excavation and backfill meet MnDOT Specification 2451 and 2105. We recommend using
MnDOT Specification 3149.2B2, Select Granular Borrow, for backfill adjacent to the abutment. This will
help in decreasing settlement at the bridge approach, decrease hydrostatic earth pressures on the
abutment wall, and allow for more uniform compaction adjacent to the bridge.
D.2.c. Design Soil Parameters
The recommended soil parameters to be used for abutment design are as follows:
Table 8. Lateral Soil Load Parameters
Soil Type Angle of Internal Friction (degrees)
Effective unit Weight
(pcf)
Coefficient of Sliding Friction Rough Concrete
Active Earth
Pressure Coefficient
At-Rest Earth Pressure
Coefficient
Select Granular Borrow
35 125 0.60 0.27 0.43
Granular Borrow 30 120 0.50 0.33 0.50
D.2.d. Embankment Settlement
We anticipate minimal (less than 1/2 foot) new fill will be placed in the vicinity of the north and south
abutments. Therefore, embankment settlement of existing soil below the new fill will be less than 1 inch
in the vicinity of these abutments due to new fill loads. However, there will be some consolidation of the
fill and underlying organic soil, especially the in-place soils that are disturbed during abutment
foundation and stem wall construction. Organic soils are more susceptible to settlement (compressibility)
than non-organic soils, however, since the proposed grade at the bridge approach embankments are
anticipated to be generally consistent with existing grades, significant additional settlement from those
Hennepin County Transportation Department Project B14-04099 September 3, 2014 Page 13
layers should be minimal. Maximizing the amount of time between subgrade and pavement placement
will help minimize long-term and differential settlement. Bituminous pavements are easier to replace
and maintain if settlement causes pavement movement compared to concrete pavements.
It is our understanding the new embankment will have the same layout and size of the existing
embankment with no widening or lengthening. If the embankment is lengthened, widened or
significantly raised, pre-loading and/or surcharging may be needed. Slope stability analyses may also be
required.
D.3. Retaining Walls
D.3.a. Foundations
Based on the fill and organic soils encountered at depth in the borings, we recommend supporting the
retaining walls on driven pipe piles. We recommend the retaining wall foundations be designed to meet
the driven pile recommendations provided in section D.1 of this report.
D.3.b. Drainage Control
We recommend installing subdrains behind the retaining walls, adjacent to the wall footings, at the
bottom of the sand layer and above the existing water table. Preferably the subdrains should consist of
perforated pipes embedded in washed gravel, which in turn is wrapped in filter fabric. Perforated pipes
encased in a filter “sock” and embedded in washed gravel, however, may also be considered.
We recommend routing the subdrains to a sump and pump capable of routing any accumulated
groundwater to a storm sewer or other suitable disposal site.
General waterproofing of retaining walls surrounding occupied or potentially occupied areas is
recommended even with the use of free-draining backfill because of the potential cost impacts related to
seepage after construction is complete.
D.3.c. Selection, Placement and Compaction of Backfill
We recommend backfill placed within 2 horizontal feet of those walls consist of sand having less than 50
percent of the particles by weight passing a #40 sieve and less than 5 percent of the particles by weight
passing a #200 sieve. Sand meeting this gradation will need to be imported. Outside of this zone, because
subsurface conditions do not favor the accumulation of water against retaining walls, it is our opinion the
rest of the active wedge be backfilled with sand containing up to 20 percent of the particles by weight
passing a #200 sieve.
Hennepin County Transportation Department Project B14-04099 September 3, 2014 Page 14
We recommend a walk behind compactor be used to compact the backfill placed within about 5 feet of
the retaining walls. Further away than that, a self-propelled compactor can be used. Compaction criteria
for below-grade walls should be determined based on the compaction recommendations provided above
in Section D.2.b.
Exterior backfill not capped with slabs or pavement should be capped with a low-permeability soil to limit
the infiltration of surface drainage into the backfill. The finished surface should also be sloped to divert
water away from the walls.
D.3.d. Configuring and Resisting Lateral Loads
The retaining wall design can be based on active earth pressure conditions if the walls are allowed to
rotate slightly. If rotation cannot be tolerated, then design should be based on at-rest earth pressure
conditions. Rotation up to 0.002 times the wall height is generally required to mobilize active earth
pressures when walls are backfilled with sand. We recommend design for earth pressure coefficients
provided in Table 8 above. Our design values also assume that the walls are drained so that water cannot
accumulate behind the walls.
D.4. Construction Quality Control
D.4.a. Observations
We recommend having a geotechnical engineer or MnDOT-certified grading and base (soils) technician
on the subgrade soils prior to the placement of embankment fills or pavements. The technician should
verify that the soils are similar to those found in the soil borings and that they are suitable for support of
the proposed construction.
D.4.b. Materials Testing
We recommend materials tests for the embankment fill, aggregate base, asphalt and concrete
pavements be performed at the frequencies dictated in the most recent version of the MnDOT Schedule
of Materials Control.
D.4.c. Pile Quality Control
We based the nominal resistance for the driven pile foundation system on our calculations using the soil
conditions present at the boring locations. To more accurately predict actual pile lengths and capacities,
we recommend designing at least 1 pile per abutments as a test pile. We recommend dynamically
monitoring these test piles in general accordance with ASTM International D 4945. Data accumulated
from dynamic testing should be used to formulate a driving/length criterion by which the remainder of
the pile should be driven. We provide this service and will gladly discuss it with you further.
Hennepin County Transportation Department Project B14-04099 September 3, 2014 Page 15
We recommend having the remaining foundation piles driven under the continuous observation of a
geotechnical engineer or a MnDOT-certified bridge inspector. Information noted for each production pile
should include but may not be limited to driving criterion, pile length, tip elevation, driving resistance,
splices and any observed damage.
After the piles have been driven to adequate bearing and have been cut off at design elevations, we
recommend inspecting them for damage and plumbness/batter. Should the piles be damaged during
driving, or should they be driven at an angle outside the plumbness or batter specifications, the
geotechnical and structural engineers should review their load-carrying capabilities. We recommend
including contingencies in the project budget for additional piles and/or longer piles in such cases.
D.4.d. Cold Weather Precautions
If site grading is anticipated during cold weather, we recommend following the cold weather precautions
cited in specification 2105.3E for embankment construction.
For concrete paving that will take place in cold weather, precautions regarding curing should be
completed per specification 2301.3M, Concrete Curing and Protection.
E. Procedures
E.1. Penetration Test Borings
The penetration test borings were drilled with a truck-mounted core and auger drill equipped with
hollow-stem auger. The borings were performed in accordance with ASTM D 1586. Penetration test
samples were taken at 2 1/2-, 5- or 10-foot intervals. Actual sample intervals and corresponding depths
are shown on the boring logs.
Penetration test boreholes that met the Minnesota Department of Health (MDH) Environmental
Borehole criteria were sealed with an MDH-approved grout.
E.2. Material Classification and Testing
E.2.a. Visual and Manual Classification
The geologic materials encountered were visually and manually classified in accordance with ASTM
Standard Practice D 2488. A chart explaining the classification system is attached. Samples were placed in
jars or bags and returned to our facility for review and storage.
Hennepin County Transportation Department Project B14-04099 September 3, 2014 Page 16
E.2.b. Laboratory Testing
The results of the laboratory tests performed on geologic material samples are noted on or follow the
appropriate attached exploration logs. The tests were performed in accordance with ASTM or AASHTO
procedures.
E.3. Groundwater Measurements
The drillers checked for groundwater as the penetration test borings were advanced, and again after
auger withdrawal. The boreholes were then backfilled or allowed to remain open for an extended period
of observation as noted on the boring logs.
F. Qualifications
F.1. Variations in Subsurface Conditions
F.1.a. Material Strata
Our evaluation, analyses and recommendations were developed from a limited amount of site and
subsurface information. It is not standard engineering practice to retrieve material samples from
exploration locations continuously with depth, and therefore strata boundaries and thicknesses must be
inferred to some extent. Strata boundaries may also be gradual transitions, and can be expected to vary
in depth, elevation and thickness away from the exploration locations.
Variations in subsurface conditions present between exploration locations may not be revealed until
additional exploration work is completed, or construction commences. If any such variations are
revealed, our recommendations should be re-evaluated. Such variations could increase construction
costs, and a contingency should be provided to accommodate them.
F.1.b. Groundwater Levels
Groundwater measurements were made under the conditions reported herein and shown on the
exploration logs, and interpreted in the text of this report. It should be noted that the observation
periods were relatively short, and groundwater can be expected to fluctuate in response to rainfall,
flooding, irrigation, seasonal freezing and thawing, surface drainage modifications and other seasonal
and annual factors.
Hennepin County Transportation Department Project B14-04099 September 3, 2014 Page 17
F.2. Continuity of Professional Responsibility
F.2.a. Plan Review
This report is based on a limited amount of information, and a number of assumptions were necessary to
help us develop our recommendations. It is recommended that our firm review the geotechnical aspects
of the designs and specifications, and evaluate whether the design is as expected, if any design changes
have affected the validity of our recommendations, and if our recommendations have been correctly
interpreted and implemented in the designs and specifications.
F.2.b. Construction Observations and Testing
It is recommended that we be retained to perform observations and tests during construction. This will
allow correlation of the subsurface conditions encountered during construction with those encountered
by the borings, and provide continuity of professional responsibility.
F.3. Use of Report
This report is for the exclusive use of the parties to which it has been addressed. Without written
approval, we assume no responsibility to other parties regarding this report. Our evaluation, analyses
and recommendations may not be appropriate for other parties or projects.
F.4. Standard of Care
In performing its services, Braun Intertec used that degree of care and skill ordinarily exercised under
similar circumstances by reputable members of its profession currently practicing in the same locality. No
warranty, express or implied, is made.
Appendix
13
7
5
3
1
1
4
TW
WH
WH
4
6
Bag samplecollected forR-value testing.
An open triangle inthe water level(WL) columnindicates the depthat whichgroundwater wasobserved whiledrilling.Groundwaterlevels fluctuate.
Sieve Analysis
Switched to mudrotary drillingmethod at 11 feet.
OC=18%
DD=28.1 pcfOC=33%UC=0.574 tsf
OC=2%
LL=52, PL=27,PI=25
6
10
10
21
25
27
165
195
176
30
49
34
27
BIT
AGG
FILL
FILL
FILL
PT
CL
CH
ML
BIT - 12 inches.
AGG BASE - 12 inches.
FILL: Clayey Sand, with Gravel, dark brown and brown,moist to wet.
FILL: Silty Sand, fine- to medium-grained, brown, moistto 9 feet then waterbearing.
With coarse grains at 9 1/2 feet.
FILL: Silty Sand, fine- to medium-grained, brown,waterbearing.
PEAT, partially decomposed, with shells and fibers,dark brown, wet.
(Swamp Deposit)
LEAN CLAY, slightly organic, trace shells, black, wet.(Swamp Deposit)
FAT CLAY, with Silt lenses, gray to dark gray, wet, verysoft.
(Alluvium)
SILT with SAND, fine- to medium-grained, dark gray,waterbearing, very loose.
(Alluvium)
937.3
936.3
932.3
926.3
923.3
916.3
913.3
911.3
1.0
2.0
6.0
12.0
15.0
22.0
25.0
27.0
7/7/14 1" = 4'DATE: SCALE:DRILLER:
Tests or NotesWL
Braun Intertec Corporation ST-1 page 1 of 4
3 1/4" HSA, AutohammerM. Nolden
L O G O F B O R I N G(S
ee D
escr
iptiv
e T
erm
inol
ogy
she
et fo
r ex
plan
atio
n of
abb
revi
atio
ns)
LOCATION: Northing: 159567; Easting: 440944.See attached sketch.
(Soil-ASTM D2488 or D2487, Rock-USACE EM1110-1-2908)
Description of Materials
ST-1
METHOD:
BORING:
BPF
B14-04099
LOG
OF
BORI
NG
N:\
GIN
T\PR
OJE
CTS\
AX P
ROJE
CTS\
2014
\040
99.G
PJ B
RAU
N_V
8_CU
RREN
T.G
DT
9/3
/14
10:5
1
Braun Project B14-04099GEOTECHNICAL EVALUATIONBridge ReconstructionCSAH 135 over Maxwell ChannelOrono, Minnesota
qptsf
MC%Symbol
Elev.feet938.3
Depthfeet
0.0
9
10
12
12
14
9
16
16
14
16
1
1
1 1/2
1 1/2
1 1/4
1 1/4
Sieve Analysis25
23
25
24
28
23
24
18
25
28
SM
CL
SILT with SAND, fine- to medium-grained, dark gray,waterbearing, very loose.
(Alluvium) (continued)
SILTY SAND, fine-grained, dark gray, waterbearing,loose to medium dense.
(Glacial Till)
Trace Gravel encountered at 37 feet.
SANDY LEAN CLAY, trace Gravel to with Gravel, gray,wet, rather stiff to stiff.
(Glacial Till)
904.3
896.3
34.0
42.0
7/7/14 1" = 4'DATE: SCALE:DRILLER:
Tests or NotesWL
Braun Intertec Corporation ST-1 page 2 of 4
3 1/4" HSA, AutohammerM. Nolden
L O G O F B O R I N G(S
ee D
escr
iptiv
e T
erm
inol
ogy
she
et fo
r ex
plan
atio
n of
abb
revi
atio
ns)
LOCATION: Northing: 159567; Easting: 440944.See attached sketch.
(Soil-ASTM D2488 or D2487, Rock-USACE EM1110-1-2908)
Description of Materials
ST-1 (cont.)
METHOD:
BORING:
BPF
B14-04099
LOG
OF
BORI
NG
N:\
GIN
T\PR
OJE
CTS\
AX P
ROJE
CTS\
2014
\040
99.G
PJ B
RAU
N_V
8_CU
RREN
T.G
DT
9/3
/14
10:5
1
Braun Project B14-04099GEOTECHNICAL EVALUATIONBridge ReconstructionCSAH 135 over Maxwell ChannelOrono, Minnesota
qptsf
MC%Symbol
Elev.feet906.3
Depthfeet32.0
14
12
17
19
14
14
17
1 1/4
1
1 1/2
1 1/2
1 1/2
No samplerecovery.
No samplerecovery.
28
28
19
20
18
SC
CL
SANDY LEAN CLAY, trace Gravel to with Gravel, gray,wet, rather stiff to stiff.
(Glacial Till) (continued)
CLAYEY SAND, trace Gravel, gray, wet, rather stiff.(Glacial Till)
SANDY LEAN CLAY, trace Gravel, gray, wet, stiff tovery stiff.
(Glacial Till)
869.3
864.3
69.0
74.0
7/7/14 1" = 4'DATE: SCALE:DRILLER:
Tests or NotesWL
Braun Intertec Corporation ST-1 page 3 of 4
3 1/4" HSA, AutohammerM. Nolden
L O G O F B O R I N G(S
ee D
escr
iptiv
e T
erm
inol
ogy
she
et fo
r ex
plan
atio
n of
abb
revi
atio
ns)
LOCATION: Northing: 159567; Easting: 440944.See attached sketch.
(Soil-ASTM D2488 or D2487, Rock-USACE EM1110-1-2908)
Description of Materials
ST-1 (cont.)
METHOD:
BORING:
BPF
B14-04099
LOG
OF
BORI
NG
N:\
GIN
T\PR
OJE
CTS\
AX P
ROJE
CTS\
2014
\040
99.G
PJ B
RAU
N_V
8_CU
RREN
T.G
DT
9/3
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10:5
1
Braun Project B14-04099GEOTECHNICAL EVALUATIONBridge ReconstructionCSAH 135 over Maxwell ChannelOrono, Minnesota
qptsf
MC%Symbol
Elev.feet874.3
Depthfeet64.0
14
22
50/6"
2
No samplerecovery.
15
11
SP
SANDY LEAN CLAY, trace Gravel, gray, wet, stiff tovery stiff.
(Glacial Till) (continued)
Cobble layer encountered at 106 feet.
Cobbles encountered between 116 and 117 feet.
POORLY GRADED SAND, fine- to coarse-grained, withGravel and Cobbles, gray, waterbearing, very dense.
(Glacial Outwash)
END OF BORING.
Water observed at 9 feet with 9 feet of hollow-stemauger in the ground.
Boring immediately backfilled with bentonite grout.
821.3
817.8
117.0
120.5
7/7/14 1" = 4'DATE: SCALE:DRILLER:
Tests or NotesWL
Braun Intertec Corporation ST-1 page 4 of 4
3 1/4" HSA, AutohammerM. Nolden
L O G O F B O R I N G(S
ee D
escr
iptiv
e T
erm
inol
ogy
she
et fo
r ex
plan
atio
n of
abb
revi
atio
ns)
LOCATION: Northing: 159567; Easting: 440944.See attached sketch.
(Soil-ASTM D2488 or D2487, Rock-USACE EM1110-1-2908)
Description of Materials
ST-1 (cont.)
METHOD:
BORING:
BPF
B14-04099
LOG
OF
BORI
NG
N:\
GIN
T\PR
OJE
CTS\
AX P
ROJE
CTS\
2014
\040
99.G
PJ B
RAU
N_V
8_CU
RREN
T.G
DT
9/3
/14
10:5
1
Braun Project B14-04099GEOTECHNICAL EVALUATIONBridge ReconstructionCSAH 135 over Maxwell ChannelOrono, Minnesota
qptsf
MC%Symbol
Elev.feet842.3
Depthfeet96.0
9
5
4
5
6
15
7
7
5
8
16
17
Sieve Analysis
Switched to mudrotary drillingmethod at 11 feet.
Sieve Analysis
OC=17%
OC=2%
Sieve Analysis
3
11
12
20
18
24
34
19
154
28
24
23
28
BIT
AGGFILL
FILL
FILL
PT
CL
SP-SM
SW-SM
BIT - 18 inches.
AGG BASE - 6 inches.FILL: Silty Sand, fine- to medium-grained, traceGravel, brown.
FILL: Silty Sand, fine- to coarse-grained, trace Gravel,with wood pieces and trace organics, brown to 12 feetthen gray, moist to 12 feet then waterbearing.
FILL: Poorly Graded Sand with Silt, fine- tocoarse-grained, with Silt inclusions, gray, waterbearing.
PEAT, partially decomposed, with shells and fibers,dark brown, wet.
(Swamp Deposit)
LEAN CLAY, slightly organic, trace shells, black, wet.(Swamp Deposit)
POORLY GRADED SAND with SILT, fine- tocoarse-grained, trace Gravel, gray, waterbearing, looseto medium dense.
(Glacial Outwash)
WELL-GRADED SAND with SILT, fine- tocoarse-grained, trace Gravel, gray, waterbearing,medium dense.
(Glacial Outwash)
937.1936.6
929.6
921.6
919.6
916.6
914.6
909.6
1.52.0
9.0
17.0
19.0
22.0
24.0
29.0
7/8/14 1" = 4'DATE: SCALE:DRILLER:
Tests or NotesWL
Braun Intertec Corporation ST-2 page 1 of 5
3 1/4" HSA, AutohammerS. McLean
L O G O F B O R I N G(S
ee D
escr
iptiv
e T
erm
inol
ogy
shee
t for
exp
lana
tion
of a
bbre
viat
ions
)
LOCATION: Northing: 159526; Easting: 440973.See attached sketch.
(Soil-ASTM D2488 or D2487, Rock-USACE EM1110-1-2908)
Description of Materials
ST-2
METHOD:
BORING:
BPF
B14-04099
LOG
OF
BORI
NG
N:\
GIN
T\PR
OJE
CTS\
AX P
ROJE
CTS\
2014
\040
99.G
PJ B
RAU
N_V
8_CU
RREN
T.G
DT
8/2
6/14
13:
45
Braun Project B14-04099GEOTECHNICAL EVALUATIONBridge ReconstructionCSAH 135 over Maxwell ChannelOrono, Minnesota
qptsf
MC%Symbol
Elev.feet938.6
Depthfeet
0.0
16
13
15
11
21
18
19
13
23
12
30
26
31
33
25
29
25
30
25
27
SP-SM
SM
CL
WELL-GRADED SAND with SILT, fine- tocoarse-grained, trace Gravel, gray, waterbearing,medium dense.
(Glacial Outwash) (continued)
POORLY GRADED SAND with SILT, fine- tocoarse-grained, trace Gravel, dark gray, waterbearing,medium dense.
(Glacial Outwash)
SILTY SAND, fine- to medium-grained, gray,waterbearing, medium dense.
(Glacial Till)
SANDY LEAN CLAY, gray, wet, rather stiff.(Glacial Till)
901.6
894.6
879.6
874.6
37.0
44.0
59.0
64.0
7/8/14 1" = 4'DATE: SCALE:DRILLER:
Tests or NotesWL
Braun Intertec Corporation ST-2 page 2 of 5
3 1/4" HSA, AutohammerS. McLean
L O G O F B O R I N G(S
ee D
escr
iptiv
e T
erm
inol
ogy
shee
t for
exp
lana
tion
of a
bbre
viat
ions
)
LOCATION: Northing: 159526; Easting: 440973.See attached sketch.
(Soil-ASTM D2488 or D2487, Rock-USACE EM1110-1-2908)
Description of Materials
ST-2 (cont.)
METHOD:
BORING:
BPF
B14-04099
LOG
OF
BORI
NG
N:\
GIN
T\PR
OJE
CTS\
AX P
ROJE
CTS\
2014
\040
99.G
PJ B
RAU
N_V
8_CU
RREN
T.G
DT
8/2
6/14
13:
45
Braun Project B14-04099GEOTECHNICAL EVALUATIONBridge ReconstructionCSAH 135 over Maxwell ChannelOrono, Minnesota
qptsf
MC%Symbol
Elev.feet906.6
Depthfeet32.0
12
16
21
20
27
25
26
1
1 1/2
1 1/2
1 1/2
2
2
2
28
23
19
22
20
20
17
CL SANDY LEAN CLAY, trace Gravel, gray, wet, ratherstiff to very stiff.
(Glacial Till)
7/8/14 1" = 4'DATE: SCALE:DRILLER:
Tests or NotesWL
Braun Intertec Corporation ST-2 page 3 of 5
3 1/4" HSA, AutohammerS. McLean
L O G O F B O R I N G(S
ee D
escr
iptiv
e T
erm
inol
ogy
shee
t for
exp
lana
tion
of a
bbre
viat
ions
)
LOCATION: Northing: 159526; Easting: 440973.See attached sketch.
(Soil-ASTM D2488 or D2487, Rock-USACE EM1110-1-2908)
Description of Materials
ST-2 (cont.)
METHOD:
BORING:
BPF
B14-04099
LOG
OF
BORI
NG
N:\
GIN
T\PR
OJE
CTS\
AX P
ROJE
CTS\
2014
\040
99.G
PJ B
RAU
N_V
8_CU
RREN
T.G
DT
8/2
6/14
13:
45
Braun Project B14-04099GEOTECHNICAL EVALUATIONBridge ReconstructionCSAH 135 over Maxwell ChannelOrono, Minnesota
qptsf
MC%Symbol
Elev.feet874.6
Depthfeet64.0
24
21
15
2
1 1/2
1
19
20
16
SANDY LEAN CLAY, trace Gravel, gray, wet, ratherstiff to very stiff.
(Glacial Till) (continued)
Gravel layer encountered at 101 feet.
7/8/14 1" = 4'DATE: SCALE:DRILLER:
Tests or NotesWL
Braun Intertec Corporation ST-2 page 4 of 5
3 1/4" HSA, AutohammerS. McLean
L O G O F B O R I N G(S
ee D
escr
iptiv
e T
erm
inol
ogy
shee
t for
exp
lana
tion
of a
bbre
viat
ions
)
LOCATION: Northing: 159526; Easting: 440973.See attached sketch.
(Soil-ASTM D2488 or D2487, Rock-USACE EM1110-1-2908)
Description of Materials
ST-2 (cont.)
METHOD:
BORING:
BPF
B14-04099
LOG
OF
BORI
NG
N:\
GIN
T\PR
OJE
CTS\
AX P
ROJE
CTS\
2014
\040
99.G
PJ B
RAU
N_V
8_CU
RREN
T.G
DT
8/2
6/14
13:
45
Braun Project B14-04099GEOTECHNICAL EVALUATIONBridge ReconstructionCSAH 135 over Maxwell ChannelOrono, Minnesota
qptsf
MC%Symbol
Elev.feet842.6
Depthfeet96.0
96 20
SP-SM
Gravel and Cobbles encountered between 128 and 129feet.POORLY GRADED SAND with SILT, fine- tocoarse-grained, with Gravel, gray, wet, very dense.
(Glacial Outwash)
END OF BORING.
Water observed at 12 feet with 12 feet of hollow-stemauger in the ground.
Boring immediately backfilled with bentonite grout.
809.6
807.6
129.0
131.0
7/8/14 1" = 4'DATE: SCALE:DRILLER:
Tests or NotesWL
Braun Intertec Corporation ST-2 page 5 of 5
3 1/4" HSA, AutohammerS. McLean
L O G O F B O R I N G(S
ee D
escr
iptiv
e T
erm
inol
ogy
shee
t for
exp
lana
tion
of a
bbre
viat
ions
)
LOCATION: Northing: 159526; Easting: 440973.See attached sketch.
(Soil-ASTM D2488 or D2487, Rock-USACE EM1110-1-2908)
Description of Materials
ST-2 (cont.)
METHOD:
BORING:
BPF
B14-04099
LOG
OF
BORI
NG
N:\
GIN
T\PR
OJE
CTS\
AX P
ROJE
CTS\
2014
\040
99.G
PJ B
RAU
N_V
8_CU
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8/2
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Braun Project B14-04099GEOTECHNICAL EVALUATIONBridge ReconstructionCSAH 135 over Maxwell ChannelOrono, Minnesota
qptsf
MC%Symbol
Elev.feet810.6
Depthfeet128.0
0
10
20
30
40
50
60
70
80
90
100
0.0010.010.1110
SILTY SAND(SM)GRAVELSANDFINES
1.5%85.6%12.9%
D60=0.438D30=0.234D10=
Cu=Cc=
CLASSIFICATION:
GRAVELCOARSE MEDIUM
FINES
GRAIN SIZE ACCUMULATION CURVE (ASTM)
COARSE FINE SILT CLAYFINESAND
BORING: ST-1 DEPTH: 10.0'
PARTICLE DIAMETER, mm
20010040 60201043/8"1/2"3/4"1"3"
PE
RC
EN
T P
AS
SIN
G
Braun Intertec CorporationB14-04099
GS
ASTM
N:\
GIN
T\PR
OJE
CTS\
X-G
EOLA
B\1-
GIN
T FI
LES\
AX P
ROJE
CTS
GEO
LAB
\B14
-040
99.G
PJ B
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8/1
3/14
08:
40
Braun Project B14-04099GEOTECHNICAL EVALUATIONBridge ReconstructionCSAH 135 over Maxwell ChannelOrono, Minnesota
U.S. SIEVE SIZES
0
10
20
30
40
50
60
70
80
90
100
0.0010.010.1110
SILT with SAND(ML)GRAVELSANDFINES
0.0%19.1%80.9%
D60=D30=D10=
Cu=Cc=
CLASSIFICATION:
GRAVELCOARSE MEDIUM
FINES
GRAIN SIZE ACCUMULATION CURVE (ASTM)
COARSE FINE SILT CLAYFINESAND
BORING: ST-1 DEPTH: 32.5'
PARTICLE DIAMETER, mm
20010040 60201043/8"1/2"3/4"1"3"
PE
RC
EN
T P
AS
SIN
G
Braun Intertec CorporationB14-04099
GS
ASTM
N:\
GIN
T\PR
OJE
CTS\
X-G
EOLA
B\1-
GIN
T FI
LES\
AX P
ROJE
CTS
GEO
LAB
\B14
-040
99.G
PJ B
RAU
N_V
8_CU
RREN
T.G
DT
8/1
3/14
08:
40
Braun Project B14-04099GEOTECHNICAL EVALUATIONBridge ReconstructionCSAH 135 over Maxwell ChannelOrono, Minnesota
U.S. SIEVE SIZES
0
10
20
30
40
50
60
70
80
90
100
0.0010.010.1110
SILTY SAND(SM)GRAVELSANDFINES
0.0%86.4%13.6%
D60=0.295D30=0.165D10=
Cu=Cc=
CLASSIFICATION:
GRAVELCOARSE MEDIUM
FINES
GRAIN SIZE ACCUMULATION CURVE (ASTM)
COARSE FINE SILT CLAYFINESAND
BORING: ST-2 DEPTH: 5.0'
PARTICLE DIAMETER, mm
20010040 60201043/8"1/2"3/4"1"3"
PE
RC
EN
T P
AS
SIN
G
Braun Intertec CorporationB14-04099
GS
ASTM
N:\
GIN
T\PR
OJE
CTS\
X-G
EOLA
B\1-
GIN
T FI
LES\
AX P
ROJE
CTS
GEO
LAB
\B14
-040
99.G
PJ B
RAU
N_V
8_CU
RREN
T.G
DT
8/1
3/14
08:
40
Braun Project B14-04099GEOTECHNICAL EVALUATIONBridge ReconstructionCSAH 135 over Maxwell ChannelOrono, Minnesota
U.S. SIEVE SIZES
0
10
20
30
40
50
60
70
80
90
100
0.0010.010.1110
SILTY SAND(SM)GRAVELSANDFINES
8.5%77.0%14.5%
D60=0.423D30=0.183D10=
Cu=Cc=
CLASSIFICATION:
GRAVELCOARSE MEDIUM
FINES
GRAIN SIZE ACCUMULATION CURVE (ASTM)
COARSE FINE SILT CLAYFINESAND
BORING: ST-2 DEPTH: 12.5'
PARTICLE DIAMETER, mm
20010040 60201043/8"1/2"3/4"1"3"
PE
RC
EN
T P
AS
SIN
G
Braun Intertec CorporationB14-04099
GS
ASTM
N:\
GIN
T\PR
OJE
CTS\
X-G
EOLA
B\1-
GIN
T FI
LES\
AX P
ROJE
CTS
GEO
LAB
\B14
-040
99.G
PJ B
RAU
N_V
8_CU
RREN
T.G
DT
8/1
3/14
08:
40
Braun Project B14-04099GEOTECHNICAL EVALUATIONBridge ReconstructionCSAH 135 over Maxwell ChannelOrono, Minnesota
U.S. SIEVE SIZES
0
10
20
30
40
50
60
70
80
90
100
0.0010.010.1110
WELL-GRADED SAND with SILT(SW-SM)GRAVELSANDFINES
5.9%83.8%10.2%
D60=0.836D30=0.300D10=
Cu=11.6Cc=1.5
CLASSIFICATION:
GRAVELCOARSE MEDIUM
FINES
GRAIN SIZE ACCUMULATION CURVE (ASTM)
COARSE FINE SILT CLAYFINESAND
BORING: ST-2 DEPTH: 30.0'
PARTICLE DIAMETER, mm
20010040 60201043/8"1/2"3/4"1"3"
PE
RC
EN
T P
AS
SIN
G
Braun Intertec CorporationB14-04099
GS
ASTM
N:\
GIN
T\PR
OJE
CTS\
X-G
EOLA
B\1-
GIN
T FI
LES\
AX P
ROJE
CTS
GEO
LAB
\B14
-040
99.G
PJ B
RAU
N_V
8_CU
RREN
T.G
DT
8/1
3/14
08:
40
Braun Project B14-04099GEOTECHNICAL EVALUATIONBridge ReconstructionCSAH 135 over Maxwell ChannelOrono, Minnesota
U.S. SIEVE SIZES
UNCONFINED COMPRESSION TEST
Project No.: B14-04099
Date Sampled:
Remarks:
Figure 1
Client:
Project: Bridge Reconstruction
CSAH 135 over Maxwell Channel, Orono, MN
Sample Number: ST-1 Depth: 19.5-21.5'
Description: PEAT, brown (PT)
LL = PI = PL = Assumed GS= 2.70 Type: Thinwall
Sample No.
Unconfined strength, tsf
Undrained shear strength, tsf
Failure strain, %
Strain rate, %/min.
Water content, %
Wet density, pcf
Dry density, pcf
Saturation, %
Void ratio
Specimen diameter, in.
Specimen height, in.
Height/diameter ratio
1
0.574
0.287
7.8
1.00
176.2
77.7
28.1
95.2
4.9951
2.783
5.598
2.01
Com
pre
ssiv
e S
tress, ts
f
0
0.15
0.3
0.45
0.6
Axial Strain, %
0 2.5 5 7.5 10
1
Sample DetailsSample ID: W14-004800-S1 Alternate Sample ID: P-01
Date Sampled: 7/17/2014 Date Submitted: 7/17/2014
Sampled By: Matt Nolden Sampling Method: Auger Sample
Source: Insitu Soil
Material: Sandy Loam
Specification:
Location: Boring B-1
Date Tested: 7/19/2014
Test ResultsMnDOT 1305*
Maximum DryDensity (lb/ft³):
115.8
Optimum MoistureContent (%):
12.7
Material on 19.0mm Sieve: Replaced
Retained on 4.75mm Sieve(%):
10.0
Rammer Type: Hand round
Visual Description: SL Sandy Loam,fine-medium grained, brown
Dry Density - Moisture Content Relationship
Proctor Report
Braun Intertec Corporation
11001 Hampshire Avenue South
Report No: PTR:W14-004800-S1Issue No: 1
Project: B14-04099
Client: James Archer
CSAH 135 over Maxwell Channel
Hennepin County Transportation Depa1600 Prairie DriveMedina, MN, 55340
Valerie Wood, [email protected]
Bridge Reconstruction
TR:
Laboratory Results Reviewed by:
Engineering Technician II
7/19/2014Date of Issue:
Kanhai Seokaran
Phone: 952.995.2000
Minneapolis, MN 55438
Page 1 of 1Form No: 110031, Report No: PTR:W14-004800-S1 © 2000-2011 QESTLab by SpectraQEST.com
# Only ASTM and AASHTO equivalent test methods are covered by our current AAP accreditation.The 200 wash value equals 23%Phase 3, Activity 3.3
Comments
Sample DetailsSample ID: W14-004800-S1 Alternate Sample ID: P-01
Date Sampled: 7/17/2014 Date Submitted: 7/17/2014
Sampled By: Matt Nolden Sampling Method: Auger Sample
Source: Insitu Soil
Material: Sandy Loam
Specification:
Location: Boring B-1
Date Tested: 7/27/2014
Test ResultsMnDOT 1307 - 95*
R Value at 240 psi Exudation: 12
MDD (lb/ft³): 115.8
OMC (%): 12.7
R Value
Specimen ResultsNo
1Moisture Content (%) 12.4
Dry Density (lb/ft³)
Exudation Load (psi) 5895
R Value 34
213.5
3776
17
No3
Moisture Content (%) 14.7
Dry Density (lb/ft³)
Exudation Load (psi) 2638
R Value 10
R Value Report
Braun Intertec Corporation
11001 Hampshire Avenue South
Report No: RV:W14-004800-S1Issue No: 1
Project: B14-04099
Client: James Archer
CSAH 135 over Maxwell Channel
Hennepin County Transportation Depa1600 Prairie DriveMedina, MN, 55340
Valerie Wood, [email protected]
Bridge Reconstruction
TR:
Laboratory Results Reviewed by:
Laboratory Supervisor
7/28/2014Date of Issue:
Dallas Miner
Phone: 952.995.2000
Minneapolis, MN 55438
Page 1 of 1Form No: 18964, Report No: RV:W14-004800-S1 © 2000-2011 QESTLab by SpectraQEST.com
# Only ASTM and AASHTO equivalent test methods are covered by our current AAP accreditation.Phase 3
Comments
Descriptive Terminology of SoilStandard D 2487 - 00Classification of Soils for Engineering Purposes(Unified Soil Classification System)
Rev. 7/07
DD Dry density, pcfWD Wet density, pcfMC Natural moisture content, %LL Liqiuid limit, %PL Plastic limit, %PI Plasticity index, %P200 % passing 200 sieve
OC Organic content, %S Percent of saturation, %SG Specific gravityC Cohesion, psf
Angle of internal frictionqu Unconfined compressive strength, psfqp Pocket penetrometer strength, tsf
Liquid Limit (LL)
Laboratory Tests
Plas
ticity
Inde
x (P
I)
Drilling Notes
Standard penetration test borings were advanced by 3 1/4” or 6 1/4”ID hollow-stem augers unless noted otherwise, Jetting water was usedto clean out auger prior to sampling only where indicated on logs.Standard penetration test borings are designated by the prefix “ST”(Split Tube). All samples were taken with the standard 2” OD split-tubesampler, except where noted.
Power auger borings were advanced by 4” or 6” diameter continuous-flight, solid-stem augers. Soil classifications and strata depths were in-ferred from disturbed samples augered to the surface and are, therefore,somewhat approximate. Power auger borings are designated by theprefix “B.”
Hand auger borings were advanced manually with a 1 1/2” or 3 1/4”diameter auger and were limited to the depth from which the auger couldbe manually withdrawn. Hand auger borings are indicated by the prefix“H.”
BPF: Numbers indicate blows per foot recorded in standard penetrationtest, also known as “N” value. The sampler was set 6” into undisturbedsoil below the hollow-stem auger. Driving resistances were then countedfor second and third 6” increments and added to get BPF. Where theydiffered significantly, they are reported in the following form: 2/12 for thesecond and third 6” increments, respectively.
WH: WH indicates the sampler penetrated soil under weight of hammerand rods alone; driving not required.
WR: WR indicates the sampler penetrated soil under weight of rodsalone; hammer weight and driving not required.
TW indicates thin-walled (undisturbed) tube sample.
Note: All tests were run in general accordance with applicable ASTMstandards.
Particle Size IdentificationBoulders ............................... over 12”Cobbles ............................... 3” to 12”Gravel
Coarse ............................ 3/4” to 3”Fine ................................. No. 4 to 3/4”
SandCoarse ............................ No. 4 to No. 10Medium ........................... No. 10 to No. 40Fine ................................. No. 40 to No. 200
Silt ....................................... No. 200, PI 4 or below “A” line
Clay ..................................... No. 200, PI 4 and on or above “A” line
Relative Density of Cohesionless Soils
Very loose ................................ 0 to 4 BPFLoose ....................................... 5 to 10 BPFMedium dense ......................... 11 to 30 BPFDense ...................................... 31 to 50 BPFVery dense ............................... over 50 BPF
Consistency of Cohesive SoilsVery soft ................................... 0 to 1 BPFSoft ....................................... 2 to 3 BPFRather soft ............................... 4 to 5 BPFMedium .................................... 6 to 8 BPFRather stiff ............................... 9 to 12 BPFStiff ....................................... 13 to 16 BPFVery stiff ................................... 17 to 30 BPFHard ....................................... over 30 BPF
a. Based on the material passing the 3-in (75mm) sieve.b. If field sample contained cobbles or boulders, or both, add “with cobbles or boulders or both” to group name.c. Cu = D60 / D10 Cc = (D30)
2
D10 x D60
d. If soil contains 15% sand, add “with sand” to group name.e. Gravels with 5 to 12% fines require dual symbols:
GW-GM well-graded gravel with siltGW-GC well-graded gravel with clayGP-GM poorly graded gravel with siltGP-GC poorly graded gravel with clay
f. If fines classify as CL-ML, use dual symbol GC-GM or SC-SM.g. If fines are organic, add “with organic fines” to group name.h. If soil contains 15% gravel, add “with gravel” to group name.i. Sands with 5 to 12% fines require dual symbols:
SW-SM well-graded sand with siltSW-SC well-graded sand with claySP-SM poorly graded sand with siltSP-SC poorly graded sand with clay
j. If Atterberg limits plot in hatched area, soil is a CL-ML, silty clay.k. If soil contains 10 to 29% plus No. 200, add “with sand” or “with gravel” whichever is predominant.l. If soil contains 30% plus No. 200, predominantly sand, add “sandy” to group name.m. If soil contains 30% plus No. 200 predominantly gravel, add “gravelly” to group name.n. PI 4 and plots on or above “A” line.o. PI 4 or plots below “A” line.p. PI plots on or above “A” line.q. PI plots below “A” line.
Poorly graded sand h
Peat
Well-graded gravel d
PI plots on or above “A” line
PI 7 and plots on or above “A” line j
PI 4 or plots below “A” line j
Fine
-gra
ined
Soi
ls50
% o
r mor
e pa
ssed
the
No.
200
sie
ve
Coa
rse-
grai
ned
Soils
mor
e th
an 5
0% re
tain
ed o
nN
o. 2
00 s
ieve
Soils Classification
GravelsMore than 50% of
coarse fractionretained onNo. 4 sieve
Sands50% or more ofcoarse fraction
passesNo. 4 sieve
Silts and ClaysLiquid limit
less than 50
Highly Organic Soils
Silts and claysLiquid limit50 or more
Primarily organic matter, dark in color and organic odor
GroupSymbol
Criteria for Assigning Group Symbols andGroup Names Using Laboratory Tests a
Group Name b
GW
GPGMGCSWSPSM
CLMLOLOL
SC
Poorly graded gravel d
Silty gravel d f g
Clean Gravels5% or less fines e
Gravels with FinesMore than 12% fines e
Clean Sands5% or less fines i
Sands with FinesMore than 12% i
Fines classify as ML or MHFines classify as CL or CH Clayey gravel d f g
Well-graded sand h
Fines classify as CL or CHFines classify as ML or MH Silty sand f g h
Clayey sand f g h
Inorganic
Organic Liquid limit - oven driedLiquid limit - not dried
0.75
Inorganic
Organic
PI plots below “A” line
Lean clay k l m
Liquid limit - oven driedLiquid limit - not dried
0.75
CHMH
OHOH
Fat clay k l m
Elastic silt k l m
Organic clay k l m n
Organic silt k l m o
Organic clay k l m p
Organic silt k l m q
Cu 6 and 1 Cc 3 C
PT
Cu 4 and 1 Cc 3 C
Cu 4 and/or 1 Cc 3 C
Cu 6 and/or 1 CC 3 C
0 10 16 20 30 40 50 60 70 80 90 100 110
7
“U” L
ine
“A” Line
10
20
30
40
50
60
4 0
ML or OL
MH or OHCL or O
L
CH or O
H
CL - ML
Silt k l m